Power-efficient circuits are a vital step in moving towards a greener future. Battery life can get substantially improved by decreasing the amount of power a circuit needs. Lower power also leads to less excess heat generated. Electronics are within everything today – from phones and microwaves to cars! If we want to optimize the electronics to require less power, we need to understand it. In some integrated circuits that utilize bipolar transistors, it has been concluded that the main limitation regarding low-power, high-temperature operations is leakage currents that arise in reverse biased p–n junctions. There is a lack of understanding regarding the magnitude of these leakage currents, especially at higher temperatures. This thesis aims to provide an understanding of the magnitude of the leakage currents in lateral gated PNP bipolar transistors and to provide empirical models of these currents.A discussion of semiconductor physics takes place, explaining how leakage currents arise in reverse-biased pn junctions. Measurements were taken on a chip with the help of different instruments and a relay network that configured the experimental setup into different circuits while measurements were being conducted.It was shown that the leakage currents are clearly exponential to temperature, as was expected. Empirical models are created with the help of the Gauss-Newton linearization method and shown to be of the form<img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?$y=%20%5Ctheta_1%20%5Cmathrm%7Be%7D%5E%7B%5Ctheta_2%5Cleft(T-%5Ctheta_4%5Cright)%7D+%5Ctheta_3$" data-classname="equation" data-title="" />,where 𝜃 are parameters for the different models.A discussion is held on the impact of the results and how to improve upon them. Numerous sources of error are discussed, and further work is recommended.